Typical acrylic pressure sensitive adhesive formulations are copolymers of alkyl ester monomers and a functional monomer such as acrylic acid. These adhesives, however, are generally low in adhesion. While such adhesives are conventionally formulated with low levels of tackifiers (5-30%) to improve their tack and peel, tackification results in loss of heat resistance and poor aging properties. Moreover, acrylics designed for hot melts have typically been poor in shear even without tackification.
Block acrylics have been synthesized for hot melt applications to improve heat resistance, but have exhibited relatively poor adhesion. This is due to the presence of a hard block phase that stiffens the acrylic to a degree such that grab and tack are insufficient.
There continues to be a need in the art for improved acrylic polymer compositions that can be used to prepare pressure sensitive hot melt adhesive compositions that can be formulated with sufficient adhesion for applications such as industrial tapes and dermal applications.
The current invention fulfills this need.